Investigation of fibrolytic enzyme on milk production and composition, nutrients digestibility and rumen pH in early lactating Holstein cows

The aim of this experiment was to study the effect of fibrolytic enzyme on milk yield and composition, nutrient apparent digestibility and rumen pH of Holstein cows in early lactation period. Fifteen multiparous lactating cows (DIM 30 ± 10, and initial body weight 616 ±12) in change over design randomly were allocated to one of experimental diets. The experimental diets included: 1) control (with no Natuzyme enzyme added to basal diet), 2) basal diet with 2.5 g/kg of Natuzyme enzyme to kg of DM 3) basal diet with 5 g/kg of Natuzyme enzyme to kg of DM. Design had three periods and five cows allocated to each diet in each period. Individual dry matter intake and daily milk yield, milk composition weekly and body condition score (BCS) changes were measured at first and at the end of each period. Digestibility of nutrients of basal diet was measured with acid insoluble ash as marker. Rumen fluid collected for determining of pH from each cow in every period at zero and 4 h after feeding. Results indicated that 2.5 g/kg of enzyme of DM of TMR increased milk production, %3.5 fat corrected milk (FCM) and energy corrected milk (ECM) compared to the other groups (P< 0.05). Milk fat and protein yield increased significantly (P< 0.05) in group that consumed 2.5 g/kg of enzyme. Dry matter intake increased significantly in cows consumed 2.5 g and 5 g/kg of DM of enzyme (P< 0.01). Body condition score changes were improved significantly (P< 0.01) for cows consumed 5 g/kg of enzyme of DM compared to cows fed with 2.5 g/kg of enzyme and control groups. Milk efficiency decreased significantly in cows consumed 5 g/kg of enzyme (P< 0.01). Furthermore, just diet with 5 g/kg of enzyme could increase NDF and ADF digestibility in basal diet (P<0.05). The Enzyme had no any effect on rumen pH at zero and 4 h after feeding. Results of the current study indicated that the enzyme with 2.5 g/kg of DM of TMR can be useful in increasing of milk yield of early lactation Holstein cows.